China is planning to stage an annual car-free day across the country, an official with the Ministry of Construction said on Thursday.Lan Rong, director of the ministry's department of urban construction, revealed the plan at the inaugural meeting of the China Urban Public Transport Association's intelligent traffic committee in Guiyang, capital of Guizhou Province."We will promote the event in order to encourage more citizens to choose public transport instead of private cars to reduce the worsening air pollution caused by car exhausts," Lan said.